Liquid crystals and wetting on a rough substrate
By: Chi Tuong Pham
From: CFTC
At: Complexo Interdisciplinar, Anfiteatro
[2007-06-06]
When a drop of isotropic liquid is placed on a flat substrate, the interface forms at the substrate a contact angle determined by the so-called Young-Dupre law. Wenzel law assigns an effective contact angle for a droplet in the case of a rough substrate. We estimate the conditions for which the wetting behavior on a rough substrate of an ordered fluid like a nematic liquid crystal can be qualitatively different from that usually found in a simple fluid. We use the Landau-de Gennes mean field approach to investigate theoretically and numerically the complete wetting transition between a nematic liquid crystal and a periodic triangular structured substrate.